*{
    margin:0px;
    padding: 0px;
}
*,*:after,*:befoere{
	box-sizing: border-box;
}
body{
    background-size: 100% 100%;
    background-attachment: fixed;
    background:rgba(235,235,235,0.1);
    overflow: hidden;
}
*{
    box-sizing: border-box;
}

.link {
    width: 80%;
    height: 80%;
    margin:50px auto;
    text-decoration: none;
    line-height: 50px;
    font-family: "微软雅黑", Arial, Helvetica, sans-serif;
    font-weight: bolder;
    background: url("../img/welcome.png") no-repeat center center;
    transition: 1s ease;
    background-size:100% 100%;
    position: relative;
}
.link:hover{
    border: 4px solid rgba(0,0,0,0.1);
    background-position: 0px center;//鏈�鍚庝綅缃�
}
.link .line{
    display: block;
    position: absolute;
    background: none;
    transition: 0.3s ease;
}
.link:hover .line{
    background: rgba(0,0,0,0.5);
}
.link  .line-top{
    height: 4px;
    width: 0px;
    left: -100%;
    top: -4px;
}
.link:hover .line-top{
    width: 100%;
    left: -4px;
}
.link  .line-bottom{

    height: 4px;
    width: 0px;
    right: -100%;
    bottom: -4px;
}
.link:hover .line-bottom{
    width: 100%;
    right: -4px;
}
.link  .line-left{

    height: 0px;
    width: 4px;
    left:-4px;
    bottom: -100%;
}
.link:hover .line-left{
    height: 100%;
    bottom: -4px;
}
.link  .line-right{

    height: 0px;
    width: 4px;
    right: -4px;
    top: -100%;
}
.link:hover .line-right{
    height: 100%;
    top: -4px;
}